Chlamydia (genital) - including symptoms, treatment and prevention

Genital chlamydia is caused by the Chlamydia trachomatis bacterium and is the most common sexually transmitted infection (STI) in Australia.

Chlamydia trachomatis infection (sexually transmitted infections only) is a notifiable condition1

How chlamydia is spread

Chlamydia trachomatis is usually transmitted sexually.

Signs and symptoms of chlamydia

Genital chlamydia occurs in both men and women, though up to 25% of infected men and 70% of infected women may not have any symptoms, and may not know they have the infection. This doesn’t mean the infection is trivial as complications can develop even in people without symptoms. Having a current sexually transmitted infection also increases the risk of getting Human immunodeficiency virus infection (HIV) infection if you are exposed to HIV.

Chlamydia trachomatis can cause conjunctivitis (inflammation of the lining of the eyelids and eye) in both adults and babies. Babies born to infected mothers can become infected as they pass through the infected cervix and may develop conjunctivitis or pneumonia (lung infection or inflammation) caused by chlamydia soon after birth.

A small proportion of people infected with Chlamydia trachomatis develop joint pain.

Having chlamydia infection does not result in immunity, and so re-infection is common. It is likely that the most serious complications (infertility, pelvic inflammatory disease and blindness) are the result of repeated infections.


In men, chlamydia may produce a urethritis (infection of the urethra, the urinary canal leading from the bladder to exit at the tip of the penis). A discharge from the penis may be present but many infections have no symptoms. Occasionally, infection may spread to the epididymis (storage tubes for sperm that are on top of the testes), which can be very painful and may lead to infertility.


Although most infected women are without symptoms, it is women who suffer the most serious consequences of genital chlamydia infections. In women, the cervix (opening of the uterus at the top of the vagina) becomes infected. From the cervix, the infection may spread to the Fallopian tubes, which are tubes leading from the ovary to the uterus, causing pelvic inflammatory disease (PID). Pelvic inflammatory disease due to chlamydia is often without symptoms but if untreated may lead to scarring of the Fallopian tubes and ectopic (tubal) pregnancy or infertility.

Diagnosis of chlamydia

Chlamydia infection is best diagnosed by examination and PCR (polymerase chain reaction) testing in a pathology laboratory of a sample of cervical or urethral discharge. PCR tests on urine specimens may be used for screening in people without symptoms.

The infection cannot be diagnosed from a blood test.

Incubation period

(time between becoming infected and developing symptoms)

1 to 3 weeks.

Infectious period

(time during which an infected person can infect others)

Unknown, probably many months if untreated.

Treatment for chlamydia

Effective antibiotic treatment is available on prescription from a doctor. However, if infertility develops, there is no simple treatment.

For more information on treatment options, see the Chlamydia brochure (PDF 112KB)

Prevention of chlamydia

  • Practise safer sex.
  • No sex until antibiotic treatment is completed and your usual sexual partner has completed treatment.
  • A follow-up test must be done to make sure that treatment has cleared the infection.
  • All sexual partners need to be contacted, tested and treated, if indicated. Even if partners have no symptoms they may be able to transmit infection to other sexual partners.
  • Testing to exclude other sexually transmitted infections is advisable.

Useful links

1 - In South Australia law requires doctors and laboratories to report some infections or diseases to SA Health. These infections or diseases are commonly referred to as 'notifiable conditions'.